We found that while WT-PP6 reconstituted PP6−/− MEFs were highly sensitive to TNFα-mediated cell death; PP6−/− MEFs reconstituted with phosphatase-inactive D84N-PP6 or melanoma-associated G112E, H114Y, and G189R mutants remained resistant to TNFα induced cell death (Fig. 7B). The gene discussed is PPP6C; the disease is melanoma.